MACROALGAL FOOD SELECTION OF ABALONE, Haliotis discus REEVE IN RELATION TO THE BODY SIZE

Abstract

Seaweed diets for abalone are very important for aquaculture in Korea in order to promote rapid growth of abalone, Haliotis discus. This study was conducted to investigate the feeding preference of abalone using 13 macroalgal species using single and multiple choice feeding experiments. Abalone samples were sorted by the size groups of 1 cm (small group, SG), 3 cm (medium group, MG) and 5 cm (large group, LG) in each tank. After experiment, chemical compounds of water-soluble and fat-soluble extracts were then isolated from selected macroalgal species in order to investigate stimulant components for abalone feeding using agar and cellulose tests. Abalone of SG preferred mostly Ulva pertusa while MG and LG abalone preferred Undaria pinnatifida and Laminaria japonica, respectively. The abalone was attracted to a water-soluble extracts of L. japonica, U. pinnatifida and U. pertusa than those of Ecklonia cava and Sargassum sagamianum. In feeding-stimulant experiment using fat-soluble extract, the SG abalone preferred the fat-soluble extract of U. pertusa mostly while the MG and LG abalone preferred the extracts of U. pertusa and U. pinnatifida, and L. japonica, respectively. The results of feeding stimulant showed same trends as those of single-choice or multi-choice experiments. Therefore, it suggests that the food preference of H. discus is determined by feeding stimulant of seaweed rather than hardness or a form of seaweed. The feeding preference of abalone was also determined according to their body size (i.e. growing stage) and recognition of taste of seaweeds.